Why Blue Whales Don't Get Cancer - Peto's Paradox

Cancer is a scary and mysterious thing. In the process of trying to understand it, of learning to kill it, we discovered a biological

paradox

that, even today, has no solution: large animals seem to have immunity to

cancer

, which seems absurd. The larger the creature, the more

cancer

cells it is expected to have. To understand why, we must first understand the nature of cancer itself. "Kurzgesagt in a nutshell" Our cells are protein robots made up of millions of particles. Guided solely by chemical reactions, they create and destroy structures, fuel metabolism to gain energy, or produce "near" perfect copies of themselves.

We call these complex chemical reactions "pathways." They are overlapping biochemical networks, interconnected and superimposed on each other. The human mind has a hard time perceiving them, and yet they work perfectly... Until... they stop. With billions and trillions of reactions happening on these thousands of networks over the years, the question is no longer "will there be bugs?", but "when will there be?". Small mistakes add up until this huge machine breaks down. To prevent the situation from getting out of control, our cells have "buttons" that lead them to self-destruct. But these "self-destruct buttons" are not foolproof. If they fail, the cell can become a cancer cell.

Most of them are quickly neutralized by the immune system. But this is just a numbers game. Over time, the cell would multiply with undetected errors and produce more copies of itself. All animals have to face this problem. In general, cells from different animals are the same size. A mouse's cells are as large as yours, but they are fewer in number and live shorter lives. Fewer cells and a shorter lifespan mean the cells are less likely to mutate, or at least that's the assumption. Humans live 50 times longer and have a thousand times more cells than mice, but the probability of cancer remains the same in mice as in humans.

The

blue

whale, which has three thousand times more cells than us, appears to be immune to cancer. This is called "Pito's

paradox

." This makes us understand that large animals have less cancer than assumed in the article. Scientists explain the paradox in two ways; Evolution and hypertumors. The first solution: Evolo, or becoming a "bag" of cancer. With the development of multicellular creatures 600 million years ago, animals became larger and larger. Thus the cells multiplied, increasing the probability that they would suffer defects. Thus, the creatures had to invest in improving the defense system against cancer. Those who did not survive disappeared.

But cancer is not an accident. It is a process of individual errors and mutations, in some specific genes in the same cell. These are "proto-oncogenes" genes, and when they mutate, they bring bad news. For example, with the correct mutation, the cell loses the ability to self-destruct. Another mutation and he can hide. Another will look for food sources. All it takes is one more mutation and it will multiply in an instant. However, these oncogenes have an enemy: tumor suppressor genes. They prevent these critical mutations or kill the cell if the damage is irreparable. Large animals have been found to have a large number of these genes.

Therefore, elephant cells must undergo more mutations than mouse cells for the tumor to appear. They do not have immunity, but rather regenerative capabilities. This adaptation must have its costs, but scientists do not yet know what they are. Perhaps tumor suppressors lead to faster aging or difficulties in rejuvenating older people. We don't know that yet. But the solution to the paradox may be something completely different. "Hypertumors" Second solution: HYPERTUMORS (Yes.) (Yes, really.) Hypertumors get their name from hyperparasites, which are parasites of parasites. Hypertumors are tumors of tumors. We can imagine cancer as a limp in cooperation. Typically, cells cooperate to form organs, tissues or elements of the immune system, but cancer cells are "selfish" and benefit in the short term.

If they are successful, they form tumors, large clusters of cancer that are difficult to kill. However, creating a tumor requires a lot of work. Millions, billions of cancer cells multiply rapidly, requiring a lot of resources and energy. The amount of food they can steal from the body is the limiting factor for their growth. Tumor cells trick the body into building blood vessels to them, killing the body that feeds them. Here, the very nature of cancer cells can bring about their own end. Cancer cells are unstable, so they continue to undergo mutations. Some of them, much faster than their "friends".

If this continues, there will come a point where one of the copies of the original cancer cell may separate as an individual cell and stop cooperating. Which means that, like the body, the original tumor becomes an enemy fighting for those same scarce nutrients and resources. Therefore, the new mutant cells can create a hypertumor. Instead of helping, they cut off the blood supply to their "friends", which will starve the first cancer cells. Cancer kills cancer. This process can occur continuously and this can prevent cancer from becoming a problem in large organisms. Large animals may have many more of these hypertumors, but they may not grow large enough for us to detect them.

This is understood: a two-gram tumor is equivalent to 10% of the body weight of a mouse, less than 0.002% of the body weight of a human and 0.000002% of the body weight of a

blue

whale. All three tumors require the same number of cell divisions and have the same number of cells. An old blue whale may have small but insignificant cancers. Other solutions to Pito's paradox have been proposed, such as different metabolic rates or a different cellular architecture. At the moment we don't know. Scientists are working on this problem. Unlocking the secret of how these animals recover from the deadliest disease we know could pave the way to new therapies and treatments.

Cancer has always been a challenge. Today, finally, we begin to understand it. By doing this, one day we will be able to defeat him. This video was sponsored by... YOU! As?! If you want us to make more videos, you can support us on Patreon or by purchasing the best things we've created, like the Space Explorer notebook with infographic pages and cutouts to spark your creativity, or the poster set infographic, or the "Kurzgesagt" Hoodie " or, if you missed it the first time, the second edition of our gratitude journal. We dedicate time and love to our products because, just like with videos, we want to bring only good things to the world that give us pleasure.

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